Synergistic Carbon Doping and Cu Loading on Boron Nitride via Microwave Synthesis for Enhanced Atmospheric CO2 Photoreduction

Photocatalytic CO₂ reduction under atmospheric concentrations remains highly challenging yet critical for practical carbon-neutral applications. In this study, a Cu-loaded, carbon-doped boron nitride (Cu/BCN) photocatalyst was synthesized by a microwave-assisted molten salt method. This approach enables simultaneous carbon incorporation into the BN lattice and selective deposition of Cu nanoparticles, forming an efficient heterostructure. The synergy between C doping and Cu loading modulates the band structure, enhances visible-light absorption, promotes charge separation, and improves CO₂ adsorption. The optimized Cu/BCN photocatalyst achieved a CO production rate of 30.62 μmol g⁻¹ h⁻¹ with 95.8 % selectivity under ambient CO₂ conditions. Combined experimental and DFT analyses confirm that the Cu/BCN interface facilitates charge transfer and lowers the energy barrier for ∗COOH formation. This work demonstrates a promising route toward efficient CO₂ utilization directly from air, offering a scalable strategy for atmospheric carbon conversion.